428 PLAGIOSTOMATA OF THE PACIFIC, 



Japanese fish, but as these names have been long looked upon only 

 as synonyms, and as we have not access to the books in which they 

 were originally described, we have deemed it best to remove all 

 future doubts, by giving the present species the distinctive name 

 of Japonictcs. 



Heterodontus Japonicus. Mel. 



In form much resembling H. Phillippi. Supraorbital ridges, 

 strong, with large dark scutella, and a little emarginate over the 

 eye, terminating a little behind the eye and continued in front 

 towards the snout, leaving a large flat depressed space between 

 the ridges. 



The snout is very bluntly rounded. The mouth differs from 

 that of H. Phillipin in having the inner nasal fold less long, the 

 fold of the upper lip rounder and shorter, and the inferior margin 

 of the fold of the lower lip covered with soft skin with only very 

 few scutella. 



The teeth are in 23 vertical rows in both jaws, the 7 middle 

 rows of the upper jaw consist of 5 cuspid teeth, of which the 

 three middle cusps are largest, but all well marked and distinct. 

 The number of teeth in the central row is 8. The lateral cuspid 

 teeth in rows 7, 8, 16 and 17 (PI. 20, fig. 4) are more elongate, and 

 the middle cusps are less distinct than in the teeth of the more 

 central rows; in rows 6 and 18 the united cusps take the form of a 

 longitudinal crest, which corresponds with the longitudinal line on 

 the large pavement like lateral teeth (rows 1-5 and 19-23). 



In the upper jaw there are in most cases 5 teeth in each of the 

 vertical rows of pavement like teeth. Rows 3 and 21 show the 

 largest teeth in the upper jaw, whilst in the lower, rows 4 to 20 

 show the largest. The number of the rows of the pavement like 

 teeth are different in the two jaws, there being 1 rows (5 on each 

 side) in the upper, and 12 rows (6 on each side) in the lower jaw. 



All the teeth of the middle rows of the lower jaw are alike in 

 shape, those of the upper jaw (rows 8 and 17) vary considerably, 

 the lateral teeth being different from those of the central rows. 



